@Trevor - I advise you read the section on 'Before you install Windows Technical Preview' (http://windows.microsoft.com/en-gb/windows/preview-faq#faq=tab0) which does mention that: "Also, if your PC runs into problems, Microsoft will likely examine your system files. If the privacy of your system files is a concern, consider using a different PC"
I know that's not quite the same as saying "we're taking your data nya nya!" but they do at least mention they'll be sending data - and as part of a beta testing product that's pretty normal.
If you want your privacy, do like they suggest and use a different PC for your testing (or a VM, or just don't use it).
That said, if there are any privacy concerns with the full release, I'll not be upgrading!